Universal connectors for joining stringers

Abstract

This invention is a lightweight, universal connector that joins stringers at various angles. The connectors 10 are fabricated from fiber-epoxy resin strips that wrap around stringers 30 and have ends, tabs 16 and 18, which extend in one general direction. The inside surface of the first tab 16 lies on a plane defined by the stringers being joined, and the second tab 18 is separated from the first tab 16 by a distance equal to their thickness. Stringers 30 of different shapes and sizes are joined by alternately bonding the first tab 16 of one connector between the first 16 and second 18 tabs of another connector. Tee-joints are formed by using web elements 41 and 42 which each partially wrap around a stringer 3010 and have tabs 411 and 421 which are offset, and are bonded between tabs 16 and 18 of universal connectors 109 and 1010 bonded to another stringer 309. Sharp corners are trimmed from the tabs so that a gusset area remains between the stringers for support. Acute angle through obtuse angle joints are formed by trimming those edges of the tabs which lie against the stringers. A specific application of the invention is a Walker 60, utilized by handicapped individuals, fabricated from composite materials that is 40% lighter than similar metallic structures.

What is claimed as new and desired to be secured by Letters Patent of the United States is: 
     
       1. A light weight walker for aiding the handicapped, comprising: (a) a first panel for supporting loads on the walker consisting of legs and stringers connected rigidly at elbow joints and tee joints;   (b) a second panel having the same elements as the first panel;   (c) the elbow joints formed by universal connectors wrapped around and bonded to the legs and the stringers;   (d) the universal connectors comprised of at least two connector elements each having a tubular section and a tab means extending outward from the tubular section to provide an interface on which the connector elements are bonded together;   (e) the tee joints comprising a bonded combination of two web elements and two of the connector elements;   (f) the web elements each enveloping and being bonded to one-half of the outer circumference of the end of the stringer or leg where the tee joint is formed and each said web element having a tab means extending outward on both sides of the leg or stringer;   (g) an interconnecting means for holding the first panel in a fixed position relative to the second panel comprised of an interconnecting stringer and two half-stringers which allow the walker to be collapsed;   (h) the interconnecting stringer being connected to a leg of the first panel at one end and a leg of the second panel at the opposite end by means of rotating tee joints which are of the same construction as said tee joints except that the connector elements of said rotating tee joints are not bonded to the legs of the first or second panel but encircle the respective leg;   (i) the half-stringers each connected at one end to a stringer of the first panel and a stringer of the second panel, respectively by means of a joint, said joint being rotatable about a respective stringer such that the free ends of the half-stringers may rotate to a common point with the half-stringers in axial alignment;   (j) a tight fitting sleeve being slidable on the half-stringers such that it may be located over the common point to provide rigidity to the walker.   
     
     
       2. A lightweight walker as in claim 1 wherein: the half-stringers are rotatably connected against butted, right angle joints, and have connector elements that wrap around, but are not bonded to top stringers of said first and second panel.   
     
     
       3. A lightweight walker as in claim 1 wherein: a positioning means holds the half-stringers whereby said tight fitting sleeve can be positioned over said common point;   said positioning means includes two interpositioned strips bonded within one of the half-stringers, and has a rounded portion extending outward therefrom; and   said rounded portion fits within the other of the half-stringers and holds both of the half-stringers in axial alignment.